NOAA Researchers Contribute to The 3rd National Climate Assessment Revealing the Latest Impacts of Climate Change on the U.S.

Sunday, May 04, 2014

We spoke with NOAA Research’s three contributing authors to the U.S. Global Change Research Program’s 3rd National Climate Assessment (NCA) released May 6, 2014 to understand their contribution to the NCA. According to the U.S. Global Change Research Program, the 3rd NCA is a compilation of scientific information on climate change from multiple sources and institutions and is a valuable resource in communicating and understanding climate change science and the impacts of climate change on the United States. The NCA will be used by federal scientists and managers, U.S. communities and citizens, and commercial businesses to improve environmental sustainability.

Alexander is a meteorologist with NOAA and was a lead author on the Oceans and Marine Resources chapter of the 3rd National Climate Assessment.

1. What was your main contribution to the development of the Oceans and Marine Resources chapterin The Third National Climate Assessment?

My main contribution was in describing the physical changes in the ocean that have occurred or may occur in the future due to increasing greenhouse gases. This mainly focused on changes in temperature, which influences marine biology in a number of ways including changing the stratification which can impact the amount of nutrients reaching the surface. There are other changes that are underway including sea level rise, freshening (less salty) at high latitudes, and a decrease in sea ice.

2. What were the main messages from your work in this chapter, and why are these messages important to the public?

We depend on the ocean from an economic stand point and from an appreciation of nature; human induced climate change will impact both as temperatures rise and as the oceans become more acidic. For example, it’s clear that coral reefs are under great threat. Many cultures depend on the reefs as a main source of food as does the tourism industry. They are also incredibly diverse ecosystems and are simply beautiful.

3. How will your contribution to this chapter in particular be used by policymakers and scientists?

My hope is that my contribution to the Oceans and Marine Resources chapter will put the physical changes that are occurring in the ocean due to increased greenhouses gases into a broader context, so managers and scientists can more easily understand and relate to the effects of greenhouse gases on the ocean.

Thomas Knutson of NOAA's Geophysical Fluid Dynamics Laboratory

Knutson is a research meteorologist with NOAA and was a contributing author to the Our Changing Climate chapter of the 3rd National Climate Assessment.

1. What was your main contribution to the development of the chapter OurChanging Climate in The Third National Climate Assessment?

Jim Kossin (of NOAA) and I were mainly responsible for the hurricanes and climate change sections of the chapter.

2. What were the main messages from your work in this chapter, and why are these messages important to the public?

There have been increases in various measures of Atlantic hurricane activity since the 1980s. However, these are not representative of the longer-term (e.g., century-scale) behavior we see in observations. There is not a robust, significant century-scale rising trend in Atlantic hurricane frequency (after accounting for observational limitations), which also implies that we cannot yet robustly detect an influence of greenhouse warming on Atlantic hurricane activity. Despite this, we see indications of increases in hurricane intensities and hurricane-related rainfall rates in the late 21st century climate change projections from models.

Because there is not yet a detectable influence of greenhouse warming on hurricane activity, our confidence in the future projections of such influence is fairly limited. It is important that the public understand and distinguish between aspects of the climate system where climate scientists already are confident in the detection of an influence of increasing greenhouse gases on climate—such as for global mean temperature--versus cases where scientists are not yet making such a claim—such as for Atlantic hurricane activity.

3. How will your contribution to this chapter in particular be used by policymakers and scientists?

Our contributions indicate how we expect Atlantic hurricane climate will change over the coming century, which can help in climate change mitigation and adaptation planning. Our contribution also puts these projections into perspective by providing useful auxiliary information (i.e., the lack of detectable greenhouse gas influence to date on hurricanes and the relatively modest confidence in projections). This information can help policymakers and scientists understand how much confidence we have in the future hurricane activity projections and why this is the case.

Laura Petes of NOAA's Climate Program Office

Petes is an ecosystem science advisor with NOAA and was a lead author on the Coastal Zone Development and Ecosystems chapter of the 3rd National Climate Assessment.

1. What was your main contribution to the development of the Coastal Zone Development and Ecosystems chapterin The Third National Climate Assessment?

My role was to synthesize and assess the impacts of climate change on coastal ecosystems, as well as to communicate about the important role that coastal ecosystems can play in enhancing community resilience.

2. What were the main messages from your work in this chapter, and why are these messages important to the public?

We are already seeing the impacts of climate change on coastal ecosystems across the country – as increasing ocean temperatures lead to coral bleaching, changes in river flow affect wetlands, and acidifying waters threaten shellfish. Many coastal ecosystems are already degraded, in large part due to other stressors, like pollution, coastal development, and invasive species. This makes them more vulnerable to climate change.

People may not fully realize the range of benefits that we receive from ecosystems. Healthy coastal ecosystems provide us with seafood, opportunities for recreation and enjoyment, protection from storm surge and flooding, and water filtration. The National Climate Assessment serves as a reminder that these important benefits are at stake in a changing climate.

3. How will your contribution to this chapter in particular be used by policymakers and scientists?

Scientists and decision makers are working together to improve understanding of, and preparedness for, the impacts of climate change. Many Americans live, work, and play on the coast. We are already beginning to see coastal communities, natural resource managers, and citizens integrating climate information into their planning. The Coastal chapter will serve as a critical resource for informing near-term and long-term decisions.

For more information, please contact Monica Allen, director of public affairs for NOAA Research, at 301-734-1123 or by email at monica.allen@noaa.gov